Climb Glass Walls Like a Gecko With DARPA Tech

For the first time ever, a human has scaled a glass wall using a reversible adhesive inspired by gecko feet. The DARPA-funded research that developed the polymer microstructure technology on handheld paddles is part of the agency's Z-Man program. This program aims to give soldiers in urban environments ways to scale vertical walls quickly without ropes or ladders.

In one test, a human weighing 218 lb climbed up and down a 25-ft glass wall, carrying a 50-lb load and gripping a pair of the paddles, one in each hand, without using any other climbing equipment. DARPA says the materials technology that made this possible was developed by engineers at Draper Laboratory. DARPA's first demonstration of this climbing technology with humans was in February 2012. Tests have been ongoing since then, but this is the first time it's been tested while climbing glass.

During testing, an operator climbed 25 feet vertically on a glass surface using no climbing equipment except a pair of handheld paddles covered with a polymer microstructure adhesive material. The climber wore, but did not require, a safety belay. (Source: DARPA)

According to DARPA's description of the Z-Man program on its program page, the "Geckskin" material is a stiff, synthetic, reversible adhesive fabric that's been impregnated with an elastomer. Inspired by the complex structure and operation of gecko feet, researchers designed adhesive pads using this material that mimics that structure at multiple scales, including the animal's macroscopic foot tendons and the much tinier setae and spatulae on a gecko's toes.

Each individual, microscopic, stalk-like seta on a gecko foot has a bundle of hundreds of nanometer-scale spatulae, or tips, that contact the surface the animal is climbing. The gecko's toes can easily attach and detach from a surface, even one as slippery as glass, due to van der Waals intermolecular forces between that surface and the spatulae on the gecko's toes.

Because of the huge difference in scale between geckos and humans, the engineering research team created climbing paddles larger than the human hand that can balance enough adhesive force in both directions: the normal direction, perpendicular to the vertical surface, and the shear direction, parallel to the vertical surface. This keeps climbers from falling off the vertical surface each time the paddles are detached and reattached. In order to produce materials that mimic the gecko toes' microstructures and their high aspect ratio, the Draper Laboratory team also had to come up with new technologies for microfabrication and nanofabrication. These may be applicable to reversible adhesives in other applications, such as biomedical, industrial, and consumer.

Gecko feet -- and the van der Waals intermolecular forces that help them stick to almost any surface -- have been the inspiration of several different types of materials, adhesives, and gripping devices. Some we've told you about include Festo's NanoForceGripper device. Another possibility may be Boston Dynamics' six-legged RiSE climbing robot, which uses micro-clawed feet to climb vertical textured surfaces. True, it's motorized, but also true is that it's a lot bigger than a gecko yet can climb vertically (though not on glass). Boston Dynamics has remained extremely mum about how all its robots do what they do, which isn't surprising considering all were originally developed with DARPA funding.

Other robotic climbing methods are used by those that climb wind towers to do maintenance. Two we've told you about include the Helical Robotics HR 1000-LL that works by magnetics, weighs at least 90 lb and can carry an additional 50 lb or more up a wind tower shaft. The other is the International Climbing Machines robot that uses vacuum force, weighs 30 lb, and has a pull-off strength of more than 225 lb.

I agree with you Ann these are the kind of innovative ideas that people want to see where technology development. We need gadgets that help make work easier. Soldiers using this kind of energy will have the ability to move faster when they carry out their missions, no need to carry all those bulky tools with such kind of technology with them. It helps in reducing risks involved in carrying out maintenance activities on tall buildings.

"The belay rope in this test was not used, as we state in the caption. The "ladders" are part of the structure in back of the glass wall holding it up. I'm surprised DARPA didn't do a better job of giving a photo that clearly shows this accomplishment, or better yet, a video."

Ann, just kidding I know that they are using it as back up for emergency purpose.

Thanks Danyal_Ali. I think this achievement is mind-boggling. Soldiers are already carrying a lot of stuff around and don't need extra baggage, let alone the extra time and clumsiness of ropes and ladders. And that's a good point about the maintenance applications.

Nice one Ann. The ropes and ladders not only take a lot of labor and time but are also very risky comparatively. If the adhesive is not having issues with a smooth glass surface then it will work perfectly fine for rough surfaces. Moreover this technology can target a very broad market, from maintenance to soldiers in combat. I know the limitations of the size but i still hope for a gecko glove which will be much more comfortable. Anyhow, a great step forward!

Mydesign, I think you misunderstood the photo, which is confusing. The technology is mature, in that what we report did happen. The photo shows a test, not a real situation in an urban environment. The belay rope in this test was not used, as we state in the caption. The "ladders" are part of the structure in back of the glass wall holding it up.I'm surprised DARPA didn't do a better job of giving a photo that clearly shows this accomplishment, or better yet, a video.

"The DARPA-funded research that developed the polymer microstructure technology on handheld paddles is part of the agency's Z-Man program. This program aims to give soldiers in urban environments ways to scale vertical walls quickly without ropes or ladder"

Ann, the figure shows that he is using both ropes and ladders. There is no doubt that when the technology becomes matured, human beings can be climbed vertical structures as like as a spider man.

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